Angular power spectra of full−year maps. Coloured lines represent the four nulls obtained from data and simulations of the effects listed in Table 2. The purple area represents the envelope from Monte Carlo simulations as described in the text. In this figure we can appreciate that the power spectra of the data from the null maps are well matched by noise, except for a few low-ℓ points at 30GHz. Furthermore, the power spectra of the simulated systematic effects fall well below the data at all but the lowest ℓ values.